The trend in my ctDNA results has been consistent in not showing the presence of tumor material since achieving NED status. ctDNA was measured on day one of the trial and quarterly from then one. When the trial ended in 2016, because it was determined I had a confirmed complete response, the principal investigator of the trial wrote an Individual Patient Investigational New Drug Protocol that was submitted to and approved by the FDA to continue receiving the medication under the compassionate use provision as maintenance monotherapy. I am still on the medication over 8.5 years now and still receive quarterly ctDNA and twice yearly scans predominately being in the form of MRI’s. The scientific paper that resulted from the clinical trial states Foundation One was the reference laboratory used.

In April 2022 I was attending the ECOG-ACRIN (Eastern Comprehensive Oncology Group-Academy of Clinical Radiology and Imaging Network meeting [https://ecog-acrin.org/about-us/]). I am a research patient advocate member of its GI Cancers Committee. I was listening to a presentation on using ctDNA and showing data of a cohort of patients being surveilled over a long period of time. At the end of the presentation I introduced myself to the presenter as his last two slides of acknowledgments mentioned the institution where it was done at was where I participated in the trial and it also acknowledged my oncologist being involved in the study. I got it confirmed the samples I was contributing to the bio bank for research purposes were used in the study.

ctDNA has been around for years. It first came into use for a better and faster way to monitor minimal residual disease (MRD) in the blood cancers leukemia and lymphoma. The technical issues were worked out through its development and improvement to where it is used as standard practice for long-term monitoring of patient status. It was only recently introduced for solid tumor monitoring where there was a set of different technical challenges to overcome.

Colon cancer being more prevalent that other solid tumors was where the research was focused initially. A working committee at ASCO (American Society of Clinical Oncology) was established to evaluate studies leading to increasing the reliability (sensitivity and specificity) of the test. Eventually the goals were met and it received endorsement to be a part of monitoring for the early detection of reoccurrence of colon cancer.

ctDNA is being evaluated for other solid tumor types including pancreatic cancer. Researchers are working on improving the sensitivity and specificity for other solid tumors as was done for colon cancer. It is already shown to detect progression much earlier than a PET scan, CT or MRI imaging systems. While false negative and positives may occur, ctDNA is not being solely relied upon for surveillance. That is still be conventional imaging or PET scan. CT and PET involve exposure to forms of radiation. MRI involves considerably more time and is not adequate to image lungs. A CT scan is needed for lung imaging.

With respect to the use of oxaliplatin in Folfirinox, most people experience some thinning of hair on scalp and body. That was my experience with it. The rate of tumor shrinkage was significantly enhanced then when I was on “resting cycles” of 5-FU with Leucovorin.

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